This section provides background information related to the present disclosure which is not necessarily prior art.
Conventional water heater control is based on a preset user set point temperature and a fixed offset, which is the difference between the set point and the water temperature at which a heat call is generated. When the water temperature drops to a value which is a difference between the set point temperature and a predetermined offset value, the controller of the conventional water heater generates a heat call. This call for heat remains active till the water temperature reaches the preset user set point. Once the desired temperature is attained, the water temperature gradually starts decreasing due to hot water usage or heat loss and the cycle repeats.
Conventional water heaters are thus limited by a fixed offset that results in the generation of a heat call even under no usage or low usage conditions, which results in waste of electric or gas energy. Energy saving options available in the art for water heaters implement a change in the preset user set point based on water heater data that is sensed. A change in user set point results in discomfort to the user.
Water heater control typically includes different operating modes like vacation, warm, hot, very hot, and the like. Accordingly, the set point temperature is different for each of these modes to provide comfort. Hence, applying the same offset adjustment to every mode of operation may also result in discomfort for the user.
For instance, if the vacation mode set point is 70 degrees Fahrenheit and the very hot mode set point is 150 degrees Fahrenheit, applying the same offset to both modes may not be appropriate.
There is thus felt a need for controller and methods of control for water heaters that provide an energy efficient solution that does not compromise the user's comfort and at the same time is flexible enough to be implemented in any type of water heater.
As used herein, the expression ‘user set point temperature’ refers to a user expected water temperature. The expression ‘offset’ used herein refers to a value that when subtracted from the set point temperature provides a temperature at which a water heater generates a heat call. The expression ‘water usage’ used herein refers to the number of heat calls made in a predetermined time duration and the heat call ON time. These definitions are in addition to those expressed in the art.